


Semper Fidelis, Semper Fortis, Semper Eadem

by PolarisTheYoungWolf



Category: Teen Wolf (TV)
Genre: Creeper Peter, Derek and Stiles are Mates, Dirty Talk, F/M, Female Stiles Stilinski, Gender or Sex Swap, Gifset, Knotting, Lactation Kink, Military, NSFW, Nudes, Pictures, Porn With Plot, Possessive Derek, Pregnancy, Pregnancy Kink, Prompt Fic, Protective Derek, Secrets, Smut, Unplanned Pregnancy
Language: English
Status: Completed
Published: 2015-01-31
Updated: 2015-01-31
Packaged: 2018-03-09 19:53:10
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,699
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3262346
Author URL: https://archiveofourown.org/users/PolarisTheYoungWolf/pseuds/PolarisTheYoungWolf
Summary: <blockquote class="userstuff">
              <p>On Stiles' 18th birthday something happens. Scared, Stiles runs. There were things Stiles needed to sort out, needed to understand, needed to come to terms with. Also needed to becomes stronger; mentally, physically, emotionally. Hence joining that army and being away for two years. </p><p>On leave from duty, Stiles returns and reveals the new and improved Stiles.</p>
            </blockquote>





	Semper Fidelis, Semper Fortis, Semper Eadem

**Author's Note:**

> This is a prompt for india and though I tried to add in as many factors as I could, there was a limited to what I could do. I don't want to add any more chapter stories since the ones I already have, have hit a major writer's block wall, but I hope this one-shot was good enough. Maybe I'll use the other factors I didn't use in another one-shot. 
> 
> Though this is a military fic I won't spend too much time on the nitty gritty details since my knowledge of the military is limited to what I can pull off Wikipedia (and honestly my ADHD won't let me focus too much on it) and Captain America.
> 
> The transitions may seem weird or not easy flowing because I wrote the parts at different points and not in order.

When Stiles' eighteen birthday happened, she didn't think much of it. Well, back then she was a he. Other than being considered a legal adult but the government there wasn't anything special. He had no interest in smoking, so there wasn't anything really awesome about it. Lately they've been fighting random groups of monsters that were coming into Beacon. So no one was really in a celebrating mood. 

Then Stiles had to go and come in contact with a witch. She cast a spell on him and he became a she. Everyone else was busy with their own thing. Like seriously, there were monsters coming out of seemingly everywhere and keeping everyone busy and with a severe case of tunnel vision. Stiles tried to turn back to normal on his own...with the slight help from Deaton. But then the unthinkable happened. The witch who cast the spell on him died...but the spell didn't go away with her death. And because Deaton didn't know what spell she did or what potion she used, there was no way of knowing how to turn Stiles back to normal.

Stiles kept himself...herself, away from everyone. He had already been a weird one before, this was a whole new level of weird. Even if he was bi and interested in both guy and girls, or was into girls and had no problems admitting and admiring a good looking guy when he saw one, he was born and used to being a guy. Suddenly being turned into a girl was a very stressful and exhausting journey. He had friends from The Jungle who were Drag Queens and even met a few people who changed their gender and he was happy for them and understanding. They never felt right in their bodies until they made the decision...with time. 

Stiles hadn't been given time to think...hadn't been given time to adjust. Just poof! He's fought against powerful females before as well as along side them, but he wasn't an Allison or a Lydia or Kira or Cora or any of them...he was now the stereotypical damsel, too weak to save herself and always needed to be saved. 

He was so afraid of what his friends would think of him that he ran. He ran and was gone for a few weeks. All that time he wasn't sure what he did. Getting used to things wasn't really something he did though. Not even really sure how he came to the conclusion, he called up a few friends he's made over the years of fighting the supernatural that would keep his secret and forge the needed paper work. As he waited for the news he felt very much like Steve Rogers as he tried to join the army, knowing full well he shouldn't be accepted for his flaws, but still hoping. 

Somehow, he... _she_ , was accepted. 

* * *

 

After she(and yes, now Stiles identified as she) finished training and received the date of her deployment for her first tour she wrote about a five page letter to her father. She didn't explain the whole different gender thing, and oddly enough she trusted Deaton to not tell anyone about it either. Stiles explained how the need to be stronger in every sense made him want to join the army. He sent his apologies for not telling him but feared that if he saw anyone or talked to them directly, he would be talked out and he really needed to do this. 

Stiles received a surprising amount of letters when the first mail cycle happened. An equally long if not longer letter from his father asking questions as well as telling him about all that's going on. Scott and Melissa both wrote to him asking him if he was insane and to be careful and to write  and to be super extra careful and to come home safe. There was a letter from Deaton basically telling him that he knew more than everyone else and this he would keep Stiles' secret. Lydia demanded to know what the hell happened to his sanity, but also demanded he get the highest honors he could possibly get and come back in one piece. 

Other than a simple post card telling Deaton 'thank you', which basically was the end of their communication(or so she thought. Turns out that there was weird supernatural stuff happening over seas too...which shouldn't be a surprise but while being in the army Stiles was very limited with her movements. But she still wrote to him and asked for advice. It was unfair that he was more open and less cryptic over letter correspondence than in face to face scenarios. But still, he managed to help some local 'hunters' and 'protectors' with the help of the vet. Which gained him some local alliances in the supernatural front, go her!). She mostly mailed her dad, the McCalls, and Lydia. They kept her in the loop about what was going on in Beacon. Supernatural shit still hit the fan, but not anything they couldn't handle without her and no more deaths.

* * *

It was after her first tour ended that she decided she would come clean to her dad. She'd grown a lot in her time gone and she's missed her father. It killed her not being able to go on skype like the others. Stiles let her hair grow out some, let her get used to the idea of being a girl by having longer hair. It helped her ADHD mind by giving her something to fiddle with when there wasn't anything else she could have her hands on.

She asked her dad to pick her up at the airport. Though she could have told him before, she just couldn't think of a way to do so. But she kept her hair under her hat, and wore her military uniform at the baggage claim. Her face was slightly different, more feminine, but it was still Stiles. The shock was there, but God bless the Sheriff for always loving his child regardless of what happened. Stiles went into an explanation a few times since he managed to stay in Beacon long enough to interact with the McCalls and Lydia as well. She still felt weird being a girl and in Beacon, so she didn't go overly out, though Lydia managed to drag her along for a few shopping trips and giving her her best Lydia fashion advice. 

It was all too soon that Stiles was being called in for another tour. Her help and presence against the supernatural overseas didn't go unnoticed by those in the military who also knew about the supernatural. She joined this special task force that more or less hunted down people sort of like the Alpha Pack who were too powerful and too lethal to be left alone. 

She was gone for another year before that tour ended and she was back in Beacon, this time she considered staying. She'd been gone long enough that if people asked, she was more than comfortable telling them that it wasn't any of their business what she chose to do. 

What she didn't expect was the attention that followed from the older Hales. 

* * *

 

"Your uncle's a huge creep." Stiles said then mumbled a 'thank you' when Derek handed her a towel. She dried her hair as best as she could and seriously considered cutting it. She kept it long because when she looked in the mirror she saw her mom before the sickness began. And just like that she couldn't cut it...even if it was annoying at times.

Lost in thought for a moment, she failed to see how Derek's eyes roamed her body. She'd come in from the down-pour outside and it made her clothing stick to her body and Derek wanted her out of those clothes and it had very little to do with her health. 

But he shook his head from those thoughts and scoffed, "You're _j_ _ust_ figuring that out?"

"No, of course not. Before though he was just a creep wanting to be superior to humans...now he wants to _breed_ me."

The words cut through him like a knife. Rage and jealousy coursed through him like wildfire and in an instant he had Stiles trapped, both of his hands resting on either side of her head and resting on the wall behind her. " _Breed you_?"

Stiles stared up at Derek with some shock, many scenarios had ran through her head about his reaction, this one was the ones she would normally have during 'me time' because Derek's eyes were very much dilated. Looking down she also saw Derek Jr standing at attention. For a second she shrunk into herself, but then she remembered her journey. She wasn't about playing defense anymore, she was an offensive player now. 

She stood up straighter, raised her hands to Derek's neck and slid them down until they rested at his hips. He gave an instinctive buck and she tugged him a bit closer.

"Yeah...I was out running. I was wearing a tank top. My boobs aren't too big so I don't bother with a bra when I don't have to. I was sweaty but it was windy. Cold enough to make my nips visible through the fabric. I stopped to catch my breath when the perv seemingly came out of the shadows..." Stiles kept her voice steady but it was lower than normal. Intimate. Just her and Derek. She caressed her hands up Derek's body until they landed on his shoulders, "He couldn't even feign the decency of not being a pervert. Kept his electric blue eyes on my breast...every time I breathed, he followed their movement. Wanna know what he told me?"

He didn't trust himself to speak. Not sure if he'd roar with anger that Peter had seen Stiles in such a way or howl with desire. So he just nodded, feeling his incisors protrude his gums.

Stiles ran her fingers down Derek's arm which made him shudder with pleasure. With her hands over his, she guided them to her breast and let Derek cup them before continuing her story. 

"He wanted to rip my shirt off and suck on my nipples until he drew milk. He was adamant that if he sucked hard and long enough he could make it happen." she paused when Derek let out a low growl. He gave her breasts a squeeze that made her eyes close briefly, "He swore it'd taste like nectar...something about my new scent..."

Almost like instinct, Derek leaned in and took a big whiff. He licked at her neck, scent marking her in the process, "Delicious..."

"I told him he was being a Creeper Wolf."

"Should have told him to fuck off," Derek growled as he gave another squeeze.

"I did...I wanted to continue my running but he said that only riled his wolf more. Said his wolf could smell what a perfect little bitch I'd make for him to mount after a good hunting foreplay. He said that he would fill me up, put his pups inside me, make it so my body produced the milk he so desperately wants to taste from my tits. Said that I would probably take his knot with little problem...he's lying right? You guys don't actually have knots, do you?" she asked with a curious tone, rather than accusatory. It was something that embarrassed him some because he knew it was more animal than human and so far sex had been one of the things that had been pure human instinct for him. 

But thinking about knotting Stiles had a different reaction. He didn't feel ashamed that she had guessed part of what involved being a werewolf. He didn't feel like a weirdo or a freak. He felt desire. Want. Need. 

He stepped closer to her and leaned down and whispered in her ear, "I don't know...It's never happened to me. I've never knotted anyone...but I could try. Do you want that Stiles? Do you want me to try and knot you? Think you can take my cock as well as my knot?"

He held his breath, not sure if he had crossed some sort of line. If she'd snap out of whatever trans they were both in and slap him before leaving again. 

"Depends...do you want to because you want to do it with me...or are you just doing it so Peter doesn't?"

"Has he seen you like this?" Derek asked in turn.

"Yeah," she replied, which caused Derek to growl but that stopped when she lifted her shirt over her head and tossed it to the side. Derek was now presented with her bare chest and at first his mouth ran dry before it began to water. "But that's as far as he got...you can go further...if you want."

He relaxed his hands so his claws wouldn't hurt her accidentally. Cupping her breast again, but this time without the fabric of clothing between the skin to skin contact, he drew circles with his thumbs around her nipples. They'd been erecting before due to the cold, but now they were hardening even more at his actions.  

 

He picked her up and she wrapped her legs around his hips as he lead them towards the table in his loft. Kissing her with the intended desire she was causing him, he let his hands roam her body while bringing it closer to his. He wanted her to feel what she was doing to him and his wolf. 

 

Just as he's about to help Stiles out of her pants and have a taste, the loft doors open and a ticked off looking Peter steps in. Derek pulls his shirt off and tosses it to Stiles who puts it on quickly, not liking at all the way Peter's eyes run over her body. Derek pulled Peter's attention away from Stiles though by shifting and roaring at him challengingly. It wasn't hard at all to miss the scent of anger and arousal coming from...both werewolves. Peter shifted into his Beta form as well and returned the roar, not backing down. 

"You're not welcomed here." Derek growled.

"I'll leave...once I have Stiles." Peter replied.

"Like hell! Why her, anyway?" Derek asked in his typical 'Derek' like tone that would normally offend Stiles, but she knew, or hoped she knew, what he was doing. Getting info while trying to dissuade Peter.

The older wolf though took a deep breath before locking eyes on Stiles again, "Anyone with senses like ours can smell it. Smell her. She's perfect. Nice and ripe and ready for the taking. Come with me, pet...I know what I'm doing. Derek...he's just a child in comparison. You'll want a real man before getting the wolf."

Derek roared and launched himself at his uncle. They fought for what seemed like an eternity. Blood spattered here and there, things broke, before Derek gained some momentum and threw Peter out the window. 

He stood there for a moment, panting, shirtless, healing from his wounds, and Stiles thought he looked damn sexy. She must have given off a wave of arousal because Derek sniffed the air before his electric blue eyes turned and locked onto her. He pounced, crushing her to his body as he kissed her fiercely and possessively. Picking her up he led them to the bed where he laid down with her. She shimmied out of her pants as she kissed Derek, this time softer and gently. Telling him silently that she was here, with him. She chose him, not Peter. 

He smiled slightly as he ran his hand up her stomach, lifting her shirt.

 

They helped each other undress until they were just skin to skin. Their lips kissed away at each other, seemingly wanting to steal and give each other every breath they held. Derek's hands roamed and caressed her body until he rested his fingers on her womanhood. He was teasing at first, causing her to moan lightly and huff in annoyance. He smirked, which made her grip his hair to pull him down to her so she could kiss it away. As she did so, he slipped his finger inside of her. He worked her open until he added a second, then third, and then forth finger in her until practically his whole hand was inside. Her grip on his hair tighten as he kept brushing against nerves that sent hot white pleasure through her. 

 

She let out a sigh of frustration when Derek wouldn't use something bigger. Deciding to take action into her own hands, she turned them over, using the strength she had from her running with the Lacrosse team back in high school, as well as the one she gained while being in the military. Derek looked at her with furrowed brows when realization dawned on him and he smirked devilishly. She leaned down to kiss that smirk away like the one before while easing herself down on his cock. 

She took a moment to let herself adjust to his girth before beginning to move. Slow and steady at first before she picked up her pace and began to ride him. 

The view from Derek's point of view was as amazing as the sensation on his cock. He leaned his head back to lead out a mix of a moan and a howl. His wolf was so fucking pleased right now. His senses were on over drive but they were all focused on Stiles. Listening to her moans and breathing, her heartbeat, and whatever few words escaped her. Smelling the intoxicating aroma she was giving off that was driving him insane. Observing the beauty that was Stiles. Even before when she was a guy he was great to look at. Not sexy like what the media made people out to be, but beautiful in an interesting way that only _Stiles_ pulled off. His hands reached to touch any part of her he could. From her thighs, to her stomach, to her breast. Gods, he was over the moon.

 

He tilted his head back again and let out another howl of pleasure.

"W-what is that?" Stiles asked with a shaky breath. 

Derek had to focus until he realized the weird sensation around his cock that he's never felt before. "Fuck...it is real." He switched their positions. Rested her on her knees while her body collapsed onto the bed. Instincts took over and he began to thrust into her until the knot kept him from doing anything but small rutting. "Fuck...Stiles... _Stiles_ , please...can I...will you... _please_...?"

"Uh huh..." she said breathlessly, "Knot me, Sourwolf..."

That was all he needed to slowly push in. Stiles made a face of pain, Derek was huge on his own, his knot...well, it hurt. Derek placed his hand on the small of her back and black veins appeared as he took as much of the pain away. Stiles let out a sigh of relief and then Derek did too once Stiles took in all of his knot. 

He stayed still for as long as he could, letting Stiles adjust. When she nodded he let out a quiet, "Thank god." before he began to thrust. The knot kept him locked inside of her, and he filled her up, not one inch inside of her wasn't being graced by Derek's dick. 

Not much longer after that did Stiles find release, crying out Derek's name and clenching around him. He groaned and threw his head back and howled, but he could still keep doing. And he kept going. Even as Stiles collapsed and mewled at being overly sensitive right now, he kept thrusting. 

He grabbed Stiles and held her up, moving her with his strength since she didn't have any right now to do much else but enjoy Derek's cock inside of her. She gripped at anything she could. His legs, his arms, his shoulders, and scratched, drawing blood, which only made Derek hissed in pleasure. 

Stiles came the second time that time before Derek came hard inside of her with a growl of her name. 

The knot still in place kept him locked inside of her. He held her closer though as he made them comfortable in his bed, pulling the covers over them. Their breathing was all they heard as it slowly returned to normal. 

It was later that the knot deflated and Derek pulled out, but still held Stiles close to him. 

* * *

The next day Stiles spent mostly with Derek. She told him what she's been doing overseas( well what she's allowed to tell anyway. Derek may be a werewolf but the things she knew were classified for a reason. Things _she_ had to worry about since they were so far away from Beacon, not Derek).

Derek was very handsy and clingy, which Stiles had no problem with. She could get used to it....which sucked when she got an urgent call from her supervising officer telling her that she was being deployed ASAP. Her task force/team needed her expertise. 

Telling her dad, Scott, and Derek she was leaving was not easy. They argued and pouted a lot more than those three powerful men should. But she eventually got them to understand that she was being called out on duty and had a responsibility. They hated it, but she eventually left.

She was screened and tested before heading off to another part of the world where her knowledge in the weird was going to come in handy. Everything was going normal, her stomach was a bit more sensitive than usual, but other than that...normal. They were stationed somewhere in the Middle East and were prepping to head out on patrol when Stiles was called into the command center.

She furrowed her eyebrows in confusion since they've already been given their orders. Her worry must have shown on her face because her commanding officer smiled easily, "At ease. You're not in trouble."

She relaxed her shoulders some but still stayed tense with anticipation. "Sir?" she raised an eyebrow in question.

"Considering what we do, we have to make sure those on your team are checked more so than the other soldiers. Your latest exams were involved in a glitch of sorts and we didn't get the full report back until this morning."

Stiles' stomach dropped and her heart rose to her throat. "Did my test show something, sir?"

"Yes...but nothing dangerous, Privet Stilinski." he said as he passed over Stiles' file over to her. She took it tentatively before opening it.

She stared at the paper for a while before letting out a shaky breath and looking up. Her commanding officer wasn't sure what to say, not knowing if it was a good or a bad thing. So he settled on explaining what will be happening next, "You'll be heading back as soon as the arrangements are available. In the mean time...would you like to call the father?"

"The...the father? Holy crap, Derek! He's," she caught herself before losing her control. She cleared her throat, "I would...I would like to contact my family and let them know I'll be going home, sir."

Her commander nodded, "Head to your bunk and you'll be alerted once we have a communication signal set up. Dismissed."

Stiles saluted and turned to leave. But not before hearing a "Congratulation, Stilinski."

 She turned and smiled happily and nodded.

* * *

 

She called Derek first because...hello, baby daddy. It took a few rings before he answered since it was an unknown number. 

"Derek?" she was glad her voice didn't break, but it did sound small.

 _"Stiles? Are you alright? Is everything okay? Stiles? Stiles! Talk to me!_ " Derek said in panic and Stiles mind froze. 

And because it froze, whatever filter she's developed over here in combat, disappeared and she just blurted it out, "I'm pregnant!"

_"...."_

"...."

" _WHAT_?!" 

"I'm...I'm pregnant...with your child." 

_"I...I. fuck, where are you?"_

"Derek you can't just come over here, you realize that, don't you?"

_"There hell I can't! What's your location? What's the closest city, I'll get there then come to you."_

"Even if you manage to get into a war zone city or any city near a war zone, as tricky as that is these days, you really, logically expect to come marching into a fully loaded army base?" Stiles asked. 

On the other side of the line Derek Hale, ole fearsome Derek Hale who will rip your throat out with his teeth if you piss him off enough, _whimpered_. 

Stiles signed and ran a hand through her hair, "Hey...it's okay, Sourwolf. They caught me before I left for patrol. I'm resting back at the base, safe and sound. I'm heading out on the next available flight out of here, okay? I'll be home soon."

_"Not soon enough!"_

"I know...I know, babe. But I am going home. Okay, then I'll stay. I'll stay with you for as long as you'll have me. Promise."

 _"I...I...be **safe**!_ " Derek urged.

"Of course. Hey...I gotta go..."

" _NO_!"

"I have to, babe. I have to talk to dad too...unless _you_ wanna tell him?"

_"...call me when you get the chance."_

Stiles smirked, "I'll see you soon."

* * *

Soon wasn't soon enough. 

Everyone did learn that Stiles was coming back and why. Derek expected the next time the Sheriff saw him he'd either be getting punched, arrested, or shot. 

Hugged...was not what he expected in a billion years. 

But he supposed he understood some. Stiles was everything for the Sheriff, and having Stiles overseas in possible danger had put a strain on the human, it was clear to everyone. Now Stiles had a reason to stay. 

* * *

Derek got on everyone's nerves really fast. 

He kept pacing, making everyone feel antsy and nervous. He kept the channels on international news on the place he learned Stiles was located at. He actually bought a TV and paid for those specific channels. Some of the news wasn't pleasant at all but Derek refused to change it. Keeping an ear out for any planes and each hour and day that passed without hearing any bad news was a good day. Stressful as hell, but good at the end. 

Finally, FINALLY, Stiles called from the airport and told everyone she would be boarding in twenty minutes. She gave her flight number and schedule. 

Lydia got them all busy making a welcome back banner and readied Derek' loft for a small get together celebration. Welcoming her home and on the baby. 

Mostly it was to give Derek something to do and give everyone else a break from his nerves. 

* * *

Derek was actually bouncing up and down lightly, scanning the area for Stiles even though the flight wouldn't land for another two hours. 

When the flight finally did land, and Stiles all but ran towards them, Derek dropped whatever he'd been carrying and ran for Stiles. They met and embraced, he picked her up and spun her around. She was still in military uniform, so some people actually cheered and clapped at their show of affection. Once Derek let her down and asked if she was alright, she leaned up to him and kissed him. 

Some people stopped and thanked her for her service as she and Derek made the way to the others. They all got their hugs. The wolves needed to re-scent Stiles and get her smelling like pack again. They talked about everything and nothing while they waited for Stiles' bags. 

They took a two cars considering that the Sheriff, Scott, his mom, Lydia, Isaac, Kira, Cora, and Malia had come along with Derek to pick Stiles up. The Sheriff and Melissa were in front while Derek and Cora accompanied Stiles in the back. Cora being family was the one Derek allowed near his pregnant mate as they traveled home. It calmed his wolf knowing his sister was helping protect his mate and cub. 

Stiles leaned into his hold and he hugged her to him tighter. 

 

 

 

 

**Author's Note:**

> Not Beta'd, please excuse errors.
> 
> Have a prompt want to see written out? Ask in the comments or you can follow me on Twitter @_The_Young_Wolf and ask on there. Prompt posting will be on Weekends(Fri/Sat/Sun).
> 
> I'm trying to branch out and work on my smut writing abilities and also kinks so...I don't be shy.


End file.
